10 Facts About Sea Otters

1) Two separate populations of sea otters live in North America: Alaska sea otters and California sea otters.

2) Sea otters are the world’s smallest marine mammals. In California, female sea otters weigh about 50 pounds and males can reach up to 90 pounds. By comparison, the blue whale is the largest marine mammal, weighing in at around 200,000 pounds.

3) The sea otter can live its entire life without leaving the water, although Alaska sea otters do sometimes sleep, groom and nurse on land.

California sea otter floating in Morro Bay.

4) The sea otter’s fur is the densest of any animal on Earth – an estimated 650,000 to 1 million hairs per square inch. A sea otter relies on its fur to keep it warm because it doesn’t have blubber like other marine mammals do. Natural oils in a sea otter’s fur repel water and trap tiny air bubbles, providing a layer of warm air between the otter’s skin and the harsh elements of its environment.

5) Sea otters use rocks as tools to help it hunt and feed. It wedges a rock between its chest and the “armpit” of a foreleg and pounds shells against it to open them up. The sea otter also hammers rocks against strongly gripping abalone shells to pry them off of rocks and feed on their tasty insides.

6) Sea otters spend up to 48% of the daylight hours grooming their fur. They groom by rubbing fur with their forepaws. Their strong claws comb and rake the fur. Then they roll and whirl in the water to smooth their fur.

7) To keep warm, sea otters consume between 25 and 40 percent of its body weight daily, eating more than 100 different prey species.

8) To keep from drifting apart while sleeping, sea otters often snooze while holding paws.

9) Mommy sea otters pass on their individual food preferences to their pups. Some sea otters prefer to eat crabs, while others prefer mussels, and so on.

10) Although sea otters hunt for food alone, they tend to rest and sleep in same-sex groups called rafts. A raft typically contains 10 to 100 animals, with male rafts being larger than female ones.